3 monitors on a single desktop is great, but you can go one better and have multiple computers using a software KM. It still feels like a single system in that your using one keyboard/mouse but you're controlling multiple computers.
Input Director ( http://www.inputdirector.com ) is great for Windows-only setups. Another option is Synergy (a little buggy but still works okay) for mixed O/S.

As far as I'm concerned, you can never be too rich, too thin, or have too much screen space. By "screen", I mean not just large monitors, but multiple large monitors. I've been evangelizing multiple monitors since the dark days of Windows Millennium Edition: Multiple Monitors and Productivity...